| 河套灌区春小麦-萝卜复种模式下土壤NO3--N动态 |
| 摘要点击 2393 全文点击 1015 投稿时间：2005-06-06 修订日期：2005-09-14 |
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| 中文关键词 NO3--N淋失 春小麦-萝卜复种 地下水 干旱地区 河套灌区 |
| 英文关键词 NO3--N leaching spring wheat and radish multiple-crop system groundwater arid areas Hetao Irrigation District |
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| 中文摘要 |
| 研究了河套灌区春小麦-萝卜复种模式下,土壤、土壤溶液和地下水NO3--N浓度的动态变化.结果表明:随着试验时间的延长,土壤表层NO3--N含量降低,深层(100～150cm)增加;土壤溶液中、下层NO3--N浓度(70、120cm)显著高于上层(30cm),尤其是在萝卜生长季.当前的灌溉条件下,不同年度、不同生长季土壤NO3--N淋失量的多少与土壤水分的下渗量密切相关,且输入的氮素中有30%以上以NO3--N的形式淋失掉.施肥区地下水NO3--N浓度显著高于未施肥区,且65.5%的水样超过WHO规定的上限(11.3mg/L).总之,经过连续2a的春小麦与萝卜复种可使表层土壤NO3--N含量明显降低,但由于中、下层土壤剖面中残留大量的NO3--N,因此在当前灌溉措施下,短期内NO3--N淋失是不可避免的. |
| 英文摘要 |
| The NO3--N dynamics of the soil,soil solution and groundwater were studied under spring wheat and radish multiple-crop system in Hetao Irrigation District over two years.A strong tendency of NO3--N to move from upper layer to deeper layer could be observed and soil NO3--N was increased at the layer of 100～150cm.NO3--N concentration of soil solution at the depth of 70 and 120 cm was significantly higher than that at the depth of 30 cm,especially in the radish growth season.NO3--N leaching amount was correlated with deep percolation at both different crop growth seasons and different years and it accounted for higher than 30% of total N input across two years.In the fertilizer plot,the concentration of NO3--N in groundwater was far higher than that in the non-fertilizer plot,and 65.5% samples were over the safe standard of WHO(11.3mg/L) in the fertilizer plot.The topsoil NO3--N content was markedly decreased during the two years multiple-crop system.However,NO3--N leaching was inevitable in the near future due to a large amount of residual NO3--N in the middle and deeper soil profiles. |
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